1. Field of the Invention:
This invention relates to a filter device for liquids. More particularly, this invention relates to a filter device for removing blood cells and proteins from body fluids such as blood and blood plasma particularly by means of centrifugal separation.
2. Description of Prior Art:
In the field of clinical examination, chemical testing on blood is conducted in most cases by a procedure which comprises collecting a blood sample from a subject, allowing the blood sample to stand and coagulate at room temperature for 30 minutes to one hour, centrifuging the coagulated blood for 15 to 20 minutes thereby separating it into blood serum and blood plasma, adding to the blood serum such a protein coagulant as trichloroacetic acid or tungstic acid thereby coagulating proteins contained therein, and subjecting the blood serum to centrifugation thereby obtaining blood serum free from proteins, or further removing proteins the blood plasma. When the chemical test is conducted on other body fluids such as urine or spinal fluid, there are many test items which necessitate removal of proteins.
Generally when coagulated whole blood or coagulationproofed blood is separated by centrifugation into blood serum or blood plasma and the blood serum or blood plasma is further treated for removal of proteins, the practice of adding to the blood an acid solution and subsequently centrifuging the blood to isolate supernatant is followed. This practice is applied similarly to other body fluids such as urine and spinal fluid. This method is such that (a) the operation is troublesome and (b) during the separation of the blood serum, the operation must be conducted with meticulous care lest blood cells or settled proteins should mingle into the blood serum being removed. A blood collection tube containing gel has been suggested as a device enabling the operations of (a) and (b) to be performed with ease. This device has a disadvantage that blood cells remaining after the separation of blood serum is unfit for any further use. Further in the test of blood for detection of a chemical substance (d), the practice of separating chemical substances bound to proteins and free low molecular chemical substances and determining their respective concentrations independently has been gaining in popularity. In this case, again, the removal of proteins constitutes an indispensable step. As a device for centrifugally separating such proteins by means of a filter, there has been suggested a filter device which comprises a cylindrical container and a filter disposed within the container perpendicularly to the axis of the container. In the case of this device, when it is used particularly in a mobile balancing type centrifugal separator, its efficiency of filtration is extremely low because proteins are deposited on the entire surface of the filter. When this device is used for isolation of blood cells from whole blood, it provides practically no filtration because blood cells clog the fine pores of the filter. Even when the device is used in an angle-type centrifugal separator, it fails to provide desired filtration with added efficiency.
An object of this invention, therefore, is to provide a novel filter device for liquids.
Another object of this invention is to provide a filter device for the removal of blood cells and proteins from body bluids such as blood, blood plasma, urine and spinal fluid by means of centrifugation.